1. Field of the Invention
The present invention relates in general to a medical article anchoring system. In one mode, the present invention involves a catheterization system that interconnects an indwelling catheter with medical tubing and securely anchors the interconnection to a patient's skin.
2. Description of the Related Art
Medical treatment of patients commonly involves the use of percutaneously inserted catheters to deliver fluids directly into the bloodstream, a specific organ or an internal location within the patient, or to monitor vital functions of the patient. For instance, short, peripherally-inserted, intra-arteriovenous catheters are commonly used to direct fluids and/or medications directly into the bloodstream of the patient.
The fluid (e.g. parenteral liquid, medication, etc.) typically drains from a container positioned above the patient to feed under gravity or is delivered via an infusion pump. The fluid flows through tubing and thence into the indwelling catheter. The catheter and the fluid tubing are commonly removably attached to each other by a conventional luer lock connection.
A luer lock connection generally includes a male luer connector with a tapered conical portion that is adapted to fit into a correspondingly shaped receptacle of a female luer connector (i.e., a hub). A spin nut is commonly disposed on the male luer connector and is rotatable relative to the tapered conical portion. The spin nut includes internal threads that are adapted to engage external threads on the female luer connector to lock together the luer connectors. When properly engaged, the conical portion fits tightly within the receptacle to produce a sealed interconnection.
A healthcare provider can experience difficulty at times breaking the seal between the engaged conical portion and the hub of the luer lock connectors when disconnecting the male luer connector from the female luer connector. In order to aid such disconnection, some luer lock connectors include spin nuts that can slide axially between a distal position, in which the spin nut can freely rotate relative to the coupled luer connectors, and a proximal position, in which the spin nut and male luer connector are rotationally locked. The rotational lock is provided to assist in breaking the sealed coupling between the corresponding surfaces of the conical portion and the hub of the interengaged luer lock connectors.
An example of this type of luer lock connector is described in U.S. Pat. No. 5,620,427, which issued Apr. 15, 1997 to Werschmidt et al. (referred to below as “the '427 patent”). The disclosed connector provides tapered engagement surfaces providing a gradual frictional engagement when tightening the spin nut to minimize inadvertent reverse rotation and loosening of the spin nut. Also, a plurality of axially extending splines for engagement with a plurality of inwardly, radially directed ribs on the spin nut allow positive rotationally locking of the spin nut and the male luer connector when the spin nut is in a proximal position. The spin nut, when locked with the male luer connector, provides greater leverage to produce more torque on the male luer connector to break the sealed coupling.
In common practice, a healthcare provider uses adhesive, foam or surgical tape to maintain the luer lock connector, and thus the catheter, in place on the skin of the patient. The healthcare provider wraps a thin piece of tape around the luer lock connector and then forms a “chevron” with the tape, placing the ends next to the sides of the indwelling catheter. The healthcare provider then places one piece of tape across and over the connector, forms a loop in the tubing, places another piece of tape across the tubing loop, and places yet an additional piece of tape over the catheter hub and the tubing section that has been looped around and extends next to the indwelling catheter. This step forms a safety loop in the tubing so that any tension applied to the tubing does not directly pass to the catheter cannula, but rather is absorbed by the slack of the safety loop. Subsequently, the healthcare provider typically covers the insertion site and the indwelling catheter with a transparent dressing.
The entire taping and dressing procedure takes several minutes of the healthcare provider's valuable time. In addition, the catheterization process often requires relatively frequent disconnection between the catheter and the fluid supply tube, as well as dressing changes. For instance, intravenous catheterization is frequently maintained for several days, depending upon the condition of the patient. The tubing is generally replaced every 48 to 72 hours in order to maintain the sterility of the fluid and the free-flow of the fluid through the tubing. A healthcare provider thus must frequently change the tubing and re-tape the connection. The healthcare provider also must frequently clean the insertion site about the indwelling catheter and change the dressings. Moreover, the tape, which secures the catheter to the skin of the patient, often covers the cannula insertion point. The healthcare provider must remove the tape to inspect the insertion point for inflammation or infection, and must then repeat the above-described taping procedure.
The healthcare provider thus uses a great deal of valuable time applying, removing and reapplying tape. The frequent application and removal of the tape also commonly excoriates the patient's skin about the insertion site.
In addition, the traditional method of intravenous catheter securement—surgical tape and transparent dressings alone—have not always prevented catheter migration and/or dislodgment. Taped intravenous catheters are also easily pulled out during a “routine” dressing change, especially by inexperienced healthcare providers. And if the catheter migrates too far or dislodgment occurs, the healthcare provider must replace the catheter, thus exacerbating the time and expense required to maintain the intravenous feed. Such catheter re-starts also poses the risk of needle stick to the healthcare provider.
Prior securement methods have not served the patient as well. Surgical tape or foam strips are uncomfortable. Many patients also do not rest comfortably and worry about catheter dislodgment when they move, when only tape and a dressing secure the catheter in place.
Several additional drawbacks result from the use of tape to stabilize the catheter. One is contamination. Healthcare providers often tear off small strips of tape and place them on the hand rail on the patient's bed. Clostridium and other bacteria commonly exist on these surfaces and can be transferred to the patient's skin in the proximity of the insertion site.
In addition, tape securement requires the healthcare provider to handle the tape while wearing protective latex gloves. Tearing adhesive tape tends to produce microscopic and/or visible holes in the gloves and thus destroys glove barrier protection.
A number of catheter securement systems have been developed to obviate the need for frequent application of tape to secure a catheter to a patient. One such securement system is disclosed in U.S. Pat. No. 5,456,671, issued Dec. 10, 1995, to Steven F. Bierman, M. D. (hereinafter referred to as “the '671 patent”). The preferred form of the securement system disclosed in this patent involves a retainer having a plurality of lateral slots. Each slot has a similar size and is designed to receive a collar of an associated catheter connector or adaptor. The cooperating structure of the connector and the retainer, i.e., the slots and the collar, arrests longitudinal movement of the connector through the retainer, and permits quick insertion of the connector into the retainer. The healthcare provider need not worry about the rotational orientation of the connector above the retainer and only need to align coarsely the collar of the connector above the series of slots before pushing the connector into the retainer.
The retainer, which is disclosed in the '671 patent, does not work as well with the connector disclosed in the '427 patent. As noted above, the connector disclosed in the '427 patent has a plurality of axially extending splines that are spaced around a portion of the circumference of the connector's tubular body. At least one of these splines has a longer length than that of at least one of the other splines. Because the slots in the illustrated form of the retainer disclosed in the '671 patent all have the same size, the rotational orientation of the connector becomes important before the connector is inserted into the retainer. Insertion of the connector into the retainer thus requires more effort and care, thereby decreasing the ease of using the securement system disclosed in the '671 patent.